Sperm

About: Sperm is a research topic. Over the lifetime, 43420 publications have been published within this topic receiving 1316145 citations.

Evidence for decreasing quality of semen during past 50 years.

Abstract: OBJECTIVE--To investigate whether semen quality has changed during the past 50 years. DESIGN--Review of publications on semen quality in men without a history of infertility selected by means of Cumulated Index Medicus and Current List (1930-1965) and MEDLINE Silver Platter database (1966-August 1991). SUBJECTS--14,947 men included in a total of 61 papers published between 1938 and 1991. MAIN OUTCOME MEASURES--Mean sperm density and mean seminal volume. RESULTS--Linear regression of data weighted by number of men in each study showed a significant decrease in mean sperm count from 113 x 10(6)/ml in 1940 to 66 x 10(6)/ml in 1990 (p < 0.0001) and in seminal volume from 3.40 ml to 2.75 ml (p = 0.027), indicating an even more pronounced decrease in sperm production than expressed by the decline in sperm density. CONCLUSIONS--There has been a genuine decline in semen quality over the past 50 years. As male fertility is to some extent correlated with sperm count the results may reflect an overall reduction in male fertility. The biological significance of these changes is emphasised by a concomitant increase in the incidence of genitourinary abnormalities such as testicular cancer and possibly also cryptorchidism and hypospadias, suggesting a growing impact of factors with serious effects on male gonadal function.

Laboratory manual for the examination of human semen and semen-cervical mucus interaction.

Abstract: This laboratory manual consists of 2 sections which describe methods of examination of human semen and semen-cervical mucus interaction in order to standardize procedures and facilitate evaluation and comparison of research reports The section on semen collection and examination discusses and makes recommendations for sample collection and delivery; initial examination; motility assessment estimation of sperm density; examination of particulate debris; agglutination; sperm viability; counting the spermatozoa; and analysis of morphological characteristics of germinal cells including preparation of seminal fluid smears staining method and classification and quantification of germinal cells and leucocytes Photomicrographs are provided to demonstrate morphological characteristics of normal and abnormal mature sperm immature germinal cells and leucocytes and epithelial cells Appendices provide information on frequency of various sperm forms in a normal ejaculate Papanicolaou staining procedure for sperm and the Bryan/Leishman stain for seminal fluid morphology smears A sample record for sperm analysis is also included The section on sperm-cervical mucus interaction describes the composition and characteristics of the mucus the collection procedure storage and preservation and evaluation including pH Methods of evaluating sperm-cervical mucus interaction are then described The timing and techniques of the post-coital test vaginal pool sample exocervical and low cervical samples and endocervical samples and their interpretation are discussed Instructions are provided for in vitro studies including the capillary tube test and the slide technique

Sperm competition and sexual selection

Abstract: General Themes: G.A. Parker, Sperm Competition and the Evolution of Ejaculates: Towards a Theory Base. A.P. Moller, Sperm Competition and Sexual Selection. W.G. Eberhard, Female Roles in Sperm Competition. J. Wright, Paternity and Paternal Care. Taxonomic Treatments: L.F. Delph and K. Havens, Pollen Competition in Flowering Plants. D.R. Levitan, Sperm Limitation, Gamete Competition and Sexual Selection in External Fertilizers. N.K. Michiels, Mating Conflicts and Sperm Competition in Simultaneous Hermaphrodites. B. Baur, Sperm Competition in Molluscs. M.A. Elgar, Sperm Competition and Sexual Selection in Spiders and Other Arachnids. L.W. Simmons and M.T. Siva-Jothy, Sperm Competition in Insects: Mechanisms and the Potential for Selection. C.W. Petersen and R.R. Warner, Sperm Competition in Fishes. T.R. Halliday, Sperm Competition in Amphibians. M. Olsson and T. Madsen, Sexual Selection and Sperm Competition in Reptiles. T.R. Birkhead, Sperm Competition in Birds: Mechanisms and Function. D.A. Taggart, W.G. Breed, P.D. Temple-Smith, A. Purvis, and G. Shimmin, Reproduction, Mating Strategies and Sperm Competition in Marsupials and Monotremes. M. Gomendio, A.H. Harcourt, and E.R.S. Roldan, Sperm Competition in Mammals. T.R. Birkhead and A.P. Moller, Sperm Competition, Sexual Selection and Different Routes to Fitness. Index.

Development of an assay to assess the functional integrity of the human sperm membrane and its relationship to other semen characteristics

Abstract: The objective of this study was to develop a relatively simple test to evaluate the functional integrity of the membranes of human spermatozoa. As in some other species, human spermatozoa 'swell' under hypo-osmotic conditions due to the influx of water and the expansion of the membranes. A mixture of equal parts of fructose and sodium citrate (150 mosmol) with calculated ionic strength of 0.15 resulted in a maximal number of clearly identifiable swollen spermatozoa. Only small variations were seen when different aliquants of the same semen samples were separately evaluated. A high correlation (r = 0.94) was obtained between expected and observed values of swollen spermatozoa when known amounts of heat-treated spermatozoa, unable to undergo swelling, were added to untreated spermatozoa. A good correlation (r = 0.90) was also observed between the % spermatozoa in a semen sample that were capable of undergoing swelling and the % of denuded hamster oocytes that were penetrated by capacitated spermatozoa from the same semen sample. By contrast, the correlations between % sperm swelling in ejaculates and % normal sperm forms, % motile spermatozoa and % spermatozoa that do not stain with eosin-Y (supravital stain) in the same ejaculates were 0.30, 0.61 and 0.52, respectively. Therefore, the hypoosmotic swelling technique to evaluate the functional integrity of the sperm membrane appears to give high repeatability and accuracy and is closely correlated to the in-vitro fertilizing ability of spermatozoa. It may be a useful addition to the standard semen analysis.